If you wish to know whether the results of your experiment are likely to have been obtained by chance, you should use

The F-ratio can be made larger

A) only by increasing the between-groups mean square. B) only by increasing the within-groups mean square. C) by increasing the within-groups mean square or by decreasing the between-groups mean square. D) by increasing the between-groups mean square or by decreasing the within-groups mean square.

How many Native American tribes are recognized today by the federal government?

A. 355 B. 5 C. more than 550 D. 55 E. 450